WO2003067268A1

WO2003067268A1 - Capacity load type probe, and test jig using the same

Info

Publication number: WO2003067268A1
Application number: PCT/JP2003/001277
Authority: WO
Inventors: Wasuke Yanagisawa; Makoto Nakakoji; Ryo Horie; Takuto Yoshida
Original assignee: Yokowo Co., Ltd.
Priority date: 2002-02-07
Filing date: 2003-02-06
Publication date: 2003-08-14
Also published as: JPWO2003067268A1; US20050088189A1; US7233156B2; EP1482313A4; TWI278631B; DE60317638T2; MY139934A; AU2003207078A1; DE60317638D1; EP1482313B1; EP1482313A1; TW200303423A; JP4707322B2

Abstract

A movable pin (11) having a movable projection length at the front end is disposed and a plurality of probes, such as a signal probe (3) and a power supply probe (4), are disposed to extend through a metal block (1) to allow the front end of the movable pin to project at one surface side of the metal block (1). A test subject device (20) is pressed against one surface side of the metal block (1) to contact the electrode terminals (21-24) of the test subject device with the front ends of the individual probes, thereby testing the test subject device for its characteristics. At least some of these probes are formed around the outer periphery thereof with a dielectric layer and a metal film, thereby providing a capacitor load type probe having a capacitor formed therein. As a result, noise elimination can be reliably effected, and using it as a power supply probe makes it possible to suppress voltage drop across the power supply terminals even if the output varies.

Description

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Capacitively loaded probe and jig using it

The present invention is intended for high-frequency and high-speed applications, such as amplifier circuits and mixer circuits incorporated in mobile phones (an analog device with a high frequency is called a high frequency, and a digital device with a very small pulse width and pulse interval is called a high speed. The same shall apply hereinafter) when inspecting high-frequency / high-speed devices for inspecting semiconductor wafers, ICs, or modules, etc., while ensuring the connection between the device to be inspected and the inspection equipment, and exogenous noise. TECHNICAL FIELD The present invention relates to a capacity-loaded probe capable of minimizing the effect of a probe and an inspection jig using the probe. Yes)

For example, when inspecting high-frequency or high-speed devices such as semiconductor wafers, ICs or modules, if the leads and the like are exposed, it is easy to pick up noise at those parts. As shown in Fig. 12 (a), as shown in Fig. 12 (a), a spring-loaded RF signal provided in the metal block 1 (used to include both high frequency and high speed) Probe 3, power supply It is configured to be connected to the respective electrode terminals 21 to 23 of the device 20 via an inspection jig having a probe 4 for grounding and a probe 5 for grounding. With such an inspection jig, the RF signal is connected to the RF signal probe 3 via the coaxial cable 7, and the spring is compressed, so that the RF signal is connected between the device 20 to be inspected and the thin holding plate 8 on the metal work 1. A configuration that minimizes noise by preventing gaps and ensuring that the RF signal probe 3 and the electrode terminal of the device under test 20 are in contact with the electrode terminals of the device under test 20 by means of springs to input and output signals It has become. In FIG. 12A, reference numeral 6 denotes a wiring board formed of a printed circuit board or the like and forming a power supply wiring on the input side.

Even with such a structure, high-frequency or high-speed applications can easily pick up noise, and the spring-loaded probe inside the metal block 1 may pick up noise. The aforementioned Japanese Patent Application Laid-Open No. 2001-99889 discloses that the RF signal probe 3 has a coaxial structure, and a structure having no room for picking up noise is considered. On the other hand, even if high-frequency or high-speed noise is applied to the power supply terminal 23, the power supply voltage fluctuates due to the noise, and an amplifier or the like oscillates and cannot perform accurate measurement. For this reason, a circuit board (an anti-print) 6 on the input side of the power supply probe 4 is connected to a path-pass filter 6 1 consisting of a coil L and a capacitor C LC circuit as shown in Fig. 12 (b). By connecting or connecting a chip capacitor (bypass capacitor) between the input side of the power supply probe 4 and the ground on the printed circuit board (anti-print) 6, the high-frequency and high-speed A method of removing noise is used.

On the other hand, the input signal terminal is not limited to the RF signal, and various mid- to low-frequency signals ranging from a signal close to the DC level to 100 MHz are input to the input signal terminal for inspection. Even if RF noise is input to these middle and low frequency signal terminals, accurate inspection cannot be performed. Even if these medium and low frequency input signal probes are formed in a coaxial structure, they are mixed on the device side or on the inspection equipment side: RF noise will be directly input to the terminal of the device under test, As mentioned above, accurate inspection cannot be performed.

As described above, high-frequency and high-speed devices are inspected. 1 In jigs, the connection to the device under test is made less likely to be affected by noise picked up by wiring connected to the device. A contact probe having a movable pin that expands and contracts via a spring is provided in a metal block and brought into contact with the metal probe. This makes it possible to eliminate the gap between the device to be inspected and the metal block and to make a reliable connection, making it difficult to pick up noise. Furthermore, as described above, RF signal probes have been attempted to have a coaxial structure even in a metal block. On the other hand, with the development of high frequency and high speed in recent years, high integration of circuits and miniaturization of packages have been remarkable, and with the increase in the number of terminals (the number of electrodes) and the reduction in the pitch between terminals, metal Not only is the structure not using a block easily affected, but even in the case of a power supply probe in a metal block, the noise is very likely to be superimposed. Mouth-pass filling on the input side The problem with the structure with a capacitor is that it is not possible to perform accurate: | «completely without being affected by noise.

Furthermore, with the recent evolution of high-frequency and high-speed devices, changes in the input signal may cause the output to go from low to high, or the transition from no to i may cause device operation errors or forced resets. The present inventors have found that abnormalities are likely to occur in the inspection, and as a result of intensive studies on the cause, the present inventors have found that the transient time during which the output voltage changes is shortened, and the power supply generated by the voltage change accordingly It has been found that the instantaneous change in the current is based on causing a voltage drop at the power supply terminal.In other words, when the power supply current increases in a step-like manner, the structure shown in FIG. With the power probe 4 with a length of about 4 mm, the probe is thin.

It has an inductance of about 2 nH, and assuming that C ₂ = 0.5 pF as the stray capacitance around the probe, the equivalent circuit as shown in Fig. 11 (a) is obtained. (in Figure 1 1 (a), C ₂ is not necessarily capacity evening are connected, shows a stray capacitance in the equivalent circuit). As a result, so that shown for example in FIG. 1 1 (b), from the 1 0 mA current I i, the changes to A ₂ = 5 0 mA stepwise (ideal state of rise time 0), the voltage , As shown in Figure 11 (c),

The voltage dropped from 3 V to about 1.7 V, which was found to cause problems in the test data.

The present invention has been made in order to solve such a problem. Even when testing a device in which high frequency, high speed, high integration, and miniaturization of the package are required to reduce the pitch between m @@ probes, An object of the present invention is to provide a capacitance-loaded probe which is hardly affected by a voltage drop at a power supply terminal due to inductance while using a thin probe for connection to a power supply terminal.

Another object of the present invention is to reduce the noise in accordance with the signal input to the terminal of a device that is highly integrated with high frequency and high speed, thereby enabling accurate inspection without being affected by noise. And a jig for a device such as a high-frequency / high-speed device using the probe. Disclosure of the invention

A capacity-loaded probe according to the present invention includes: a metal pipe; and a movable pin that is provided in the metal pipe so as to be electrically connected to the metal pipe, and that has a variable protruding length protruding from at least one end of the metal pipe. A dielectric layer provided on an outer periphery of the metal pipe; and a first metal film provided on an outer peripheral surface of the dielectric layer, wherein a capacitance is formed between the movable pin and the first metal film. Have been.

Here, the movable pin means a pin whose tip can move along the axial direction, for example, such that when the lead wire is held and pressed by a spring or the like, the tip is contracted by the spring or the like.

By forming a capacitor on the outer peripheral surface of such a contact probe, when used as a probe connected to a power supply terminal or signal terminal, it prevents voltage drop at the power supply terminal or eliminates noise. can do. In other words, the test device under test is RF (including both high frequency with high analog frequency and high speed with short pulse of digital short pulse, and those with analog or pulse repetition of about 1 GHz or more. In other words, the voltage drop occurs when the output switches between low and high currents, for example, due to the inductance of the power supply port. It can be made as small as possible. This is based on the fact that the capacity is added to compensate for the charging and discharging of the inductance and the capacity. In addition, when connecting to the power supply terminal or the signal terminal of a signal near the DC level of the input signal or the signal terminal of a low-medium-frequency signal with a small repetition of sine wave pulse, the capacitance of the power supply probe and the signal probe is increased. By being formed, the RF noise mixed into the power supply line and the signal line can be reliably reduced by the capacity, and a highly reliable inspection can be performed without being affected by noise.

Specifically, the dielectric layer is made of a dielectric cylinder, the first metal film is formed on an outer peripheral surface of the dielectric cylinder, and a second metal film is provided on an inner peripheral surface of the dielectric cylinder. And the dielectric layer is electrically connected to the metal pipe via the second metal film, or the dielectric layer is formed of a thin film directly sworded on the outer peripheral surface of the metal pipe. A structure in which the first metal film is formed may be used. It is provided on the inner and outer walls of the dielectric cylinder. The metal film is formed by, for example, electroless plating. To form a dielectric layer with a thin film, the dielectric layer can be formed by, for example, sputtering or vacuum evaporation while rotating a metal pipe, or a liquid obtained by dissolving a dielectric material in an organic solvent or the like. It can also be formed by a sol-gel method in which it is applied to the outer periphery of a metal pipe, dried and fired.

The capacity provided on the outer periphery of the metal pipe may be formed to have two or more types of capacities.

An inspection jig according to the present invention has a metal block and a movable pin having a movable tip with a movable protruding length. The metal block is arranged so that the distal end of the movable pin protrudes from one surface of the metal protrude. A plurality of power supply and signal probes provided therethrough, and a denominated wedge is pressed against the one surface side of the metal block, and each electrode terminal of the device to be inspected and a tip of the probe A jig for making a characteristic inspection of the inspected laser by contacting the probe with at least one of the plurality of probes, wherein at least some of the plurality of probes have a dielectric layer and an outer periphery of the probe. It consists of a capacitance-loaded probe on which a metal film is provided to form a capacity.

With this structure, a RF noise bypass capacitor is formed around at least part of the power supply probe and signal probe, so that RF noise can be reduced immediately before the power supply terminal and signal terminal of the device under test. This makes it possible to bypass the power supply and signal probes, and even if the RF noise that could not be completely removed remains on the wiring board (printed circuit board) side, the bypass capacitor can be used. Completely removed. As a result, noise penetration from the power supply and mid-low frequency signal probes connected to the device via the movable pins is completely eliminated, enabling accurate inspections that are not affected by noise. . Furthermore, by using a capacitance-loaded probe for the power supply probe, the voltage drop at the power supply terminal caused by a current change inside the device can be suppressed, and within 10% of the general power supply voltage allowable range. Can be suppressed.

At least some of the signal probes connected to the signal input terminal of the device under test have at least some of the probes in accordance with the repetition of the sine wave or pulse of the signal applied to the input terminal. , The attenuation is small for the signal of the repetition and larger than the repetition By using a capacitance-loaded probe with a capacity that has the capacity to attenuate frequency noise, even if the device receives various signals from the DC level to RF at the signal input, the Since RF noise can be removed according to the input signal without attenuating the input signal, very high-precision inspection can be performed. Here, the repetition of a sine wave or a pulse means its frequency in the case of an analog signal, and its high and / or repeating speed in the case of a digital signal.

The power probe connected to the power terminal of the device under test is a capacitance-loaded probe having a capacitance of 5 OpF or more, more preferably 100 pF or more, so that the input signal The power supply voltage hardly drops by more than 10% against changes, and high-frequency noise of 400 MHz or more (200 MHz or more if 10 OpF or more) can be attenuated by 1 OdB or more. High: RF This is preferable because noise can be further attenuated and noise can be almost completely eliminated. BRIEF DESCRIPTION OF THE FIGURES

1 (a) and 1 (b) are a plan explanatory view and a partial sectional side view showing an embodiment of an inspection jig according to the present invention.

2 (a) and 2 (b) are a cross-sectional explanatory view of the capacitance-loaded probe shown in FIG. 1 and a perspective explanatory view of a dielectric tube thereof.

Fig. 3 shows the frequency characteristics of the insertion loss due to the simulation when the capacity of the probe is varied.

Fig. 4 shows the frequency characteristics of the measured insertion loss at 470 pF as an example.

FIG. 5 is an equivalent circuit diagram when a capacitance-loaded probe is used as a power supply probe.

Figures 6 (a) to 6 (c) show the state of voltage drop at the power supply terminal when the capacitance is 100 OpF and 10 OpF, compared with the case where there is no capacitance and the stray capacitance is only 0.5 pF. It is a result of the simulation performed. FIG. 7 is an explanatory cross-sectional view showing another embodiment of the capacitance-loaded probe.

FIG. 8 is an explanatory sectional view showing still another example of the capacitance-loaded probe.

FIG. 9 is a partial cross-sectional explanatory view showing another example of a structure for fixing a probe to a metal block.

FIGS. 10 (a) and 10 (b) are a cross-sectional explanatory diagram and an equivalent circuit diagram showing still another embodiment of the capacitive loaded probe.

FIGS. 11 (a) to 11 (c) are diagrams illustrating the voltage drop at the power supply terminal that occurs when a switching waveform is output.

FIGS. 12 (a) and 12 (b) are diagrams showing a configuration example of a conventional inspection jig for a high-frequency / high-speed device. BEST MODE FOR CARRYING OUT THE INVENTION

Next, a capacitance-loaded probe of the present invention and an inspection jig using the same will be described with reference to the drawings. The jig according to the present invention connects the device under test 20 to an unillustrated device, and as shown in FIGS. 1 (a) and 1 (b), a side view of a plane and a partial cross section thereof is shown. The probe has a movable pin 11 with a movable protruding length at the tip, and a signal probe 3, a power probe 4 and a ground so that the tip of the movable pin 11 protrudes from one side of the metal block 1. A plurality of probes such as a probe 5 are provided through the metal block 1. The device 20 to be inspected is pressed against one surface of the metal probe 1, and the electrode terminals 21 to 24 of the device 20 to be inspected come into contact with the tips of the probes 3 to 5, respectively. Then, the characteristic inspection of the inspection device 20 is performed. In the present invention, at least a part of the plurality of probes is a capacitance-loaded probe having a capacitance formed by providing a dielectric layer and a metal film on the outer periphery of the probe. As shown in FIG. 2 (a), a cross-sectional view of one embodiment of this capacity-loading type propellant 10 protrudes into the metal pipe 13 from at least one end of the metal pipe 13. The movable pins 11 and 12 are provided so as to be electrically connected to the metal pipe 13 so that the protruding length of the tip can be made variable, and a dielectric layer 15 is provided on the outer periphery of the metal pipe 13. The first metal film 17 is provided on the outer peripheral surface of the dielectric layer 15. Thereby, a capacitance is formed between the movable pin 11 and the first metal film 17.

In the example shown in FIG. 2, a dielectric cylinder 15 in which a dielectric is formed in a cylindrical shape is used as a dielectric layer for forming the capacity 18. Then, the second metal film 16 and the first metal film 17 are provided on the inner peripheral wall and the outer peripheral wall of the dielectric cylinder 15 by electroless plating or the like, so that the capacity 18 is formed. By providing the first and second metal films 17 and 16 on both surfaces of the dielectric tube 15, no gap is formed on both surfaces of the dielectric, so that the function of capacitance can be sufficiently achieved. I'm wearing The second metal film 16 is electrically connected to the metal pipe 13. The dielectric cylinder 15 has, for example, an inner diameter D 1 of about 0.3 mm, an outer diameter D 2 of about 0.6 mm, and a length L of, as shown in FIG. It is formed to a size of about 6 mm. This is because, as described above, the number of electrode terminals increases with the increase in integration of ICs and other devices. Recently, not only electrode terminals are provided around the chip, but the entire chip is provided by a BGA (ball grid array) package. This is because when the number of electrode terminals is large and the number of electrode terminals is large, about 400 electrode terminals are provided per cm ^2, so that the distance between the probes is very small. Of these electrode terminals, the power supply terminal is about 1/4, the ground terminal is about 1/4, and the rest is used for signal input / output terminals such as RF signals.

In order to examine the effect of this capacity 18, the inventors of the present invention determined the insertion loss with respect to the frequency when a capacitance-loaded probe having a capacity was connected to the outer surface of the probe of this structure, that is, the degree of noise reduction. Investigated by simulation. Figure 3 shows the results. Figure 3 shows the insertion loss with respect to the frequency when the capacity of the capacity shown in Fig. 2 (a) is variously changed on the vertical axis (downward). The capacity of the capacity is 10 pF, 50 The cases of pF, 100 pF, 530 pF, and 106 pF are shown, respectively. Note that no capacity indicates the frequency characteristics of a conventional probe that is not a capacitance-loaded probe.

In general, an insertion loss of about 10 dB has a great effect on noise removal, and an insertion loss of about 20 dB can almost completely eliminate the effect of noise. As can be seen from Fig. 3, if it is 160 pF, it is about 25 MHz Noise of the above frequencies can be removed, and if it is 50 MHz or more, it can be almost completely removed. For RF noise above 1 GHz, 10

It can be seen that OpF can completely eliminate the effects of noise, and that 50PF or more can sufficiently attenuate noise. On the other hand, the conventional probe without capacities (stray capacitance is considered to be about 0.5 pF) has

The insertion loss up to 0 GHz is less than 2 dB, indicating that there is almost no RF noise removal effect.

On the other hand, if the capacitance is 5 OpF, for example, there is almost no attenuation in the tens of MHz band, and significant attenuation is observed above 1 GHz. For example, in the case of a signal probe for inputting a signal, the frequency of the input signal is several tens. If the signal is below MHz, a signal loaded with RF noise is input by using a probe loaded with a capacity of about 50 pF to produce a reliable signal. The present inventors have found that they can do this. In other words, the signal probe does not attenuate the signal in accordance with the frequency of the input signal than the coaxial probe, and the capacity of the capacitor is large enough to attenuate only higher frequency noise. The present inventors have found that it is preferable to use a probe loaded with.

In order to change such a capacitance, the material of the dielectric layer 15 is changed to use a material having a different relative permittivity, or by changing the thickness of the dielectric layer 15 or the length of the probe. The capacity can be changed. For example, if barium titanate (dielectric constant 2200), which is often used as ceramics, and ceramics with a relative dielectric constant of about 38, which is called high dielectric constant ceramics, are used, Figs. 2 (a) and 2 ( By forming a probe having the structure shown in b) and the dimensions shown in Table 1, a probe having the above capacity can be formed. However, the capacitance can be freely adjusted by further changing the material and thickness of the dielectric. In particular, by forming the dielectric from a thin film as described later, the thickness can be made extremely thin, and the capacitance can be increased. 0 1 Example of capacitor formation

In fact, a capacitance-loaded probe was formed with the 530 pF capacity shown in Table 1, and the insertion loss versus frequency was measured. The result is shown in FIG. The actual capacitance was 470 pF as a result of forming with the dimensions shown in Table 1. Fig. 4 shows that, as in Fig. 3, an input loss of about 15 dB was already obtained at 50 MHz, and an input loss of almost 20 dB or more was obtained at 200 MHz or higher, indicating that noise could be almost completely removed. In Fig. 4, instruction 1 is lGHz, 27.59 5 dB, instruction 2 is 5 GHz, 33.877 dB, instruction 3 is 10 GHz, 27.66 ldB, instruction 4 is 15 GHz, 34.276 dB, and instruction 5 is 20 GH z, each showing 39.06 OdB.

As described above, if the input power is about 500 pF, a large input loss can be obtained from a sufficiently low frequency to a high frequency. Therefore, for a power supply probe, a low repetition rate (low frequency) input signal close to a DC level can be obtained. It is enough. However, as shown in Fig. 3 above, with 100 pF, there is a sufficient insertion loss at 200 MHz and above, making it practical as a power supply probe.

On the other hand, as described above, the present inventors have found that the voltage drop at the power supply terminal occurs during the transition time of the output due to the signal change due to the inductance component of the power supply probe, and an accurate test can be performed. I found that there may be no. By using a capacitance-loaded probe as the power supply probe, the voltage drop could be suppressed to 10% or less, which is not a problem. When this capacitance-loaded probe is used as a power probe, The effect of preventing voltage drop at the power supply terminal

When a capacitance-loaded probe is used as a power supply probe, the equivalent circuit of the connection to the device under test is as shown in Fig. 5. When this power supply voltage is 3 Vdc (direct current), 1 ^ = 0.10, Li-SnH, and Ci are 1000 pF and 100 pF, as shown in FIG. current from 10 mA, was examined by simulation voltage V ₂ at the power supply end terminal of when is Heni spoon stepwise (ideal state of rise time 0) to 50 mA. The results are shown in Figs. 6 (a) and 6 (b). Fig. 6 (c) shows the voltage drop when using a probe with no capacity loaded (assuming a stray capacitance of 0.5 pF), as shown in Fig. 11 (c). Are shown on the same scale as in Figures 6 (a) and 6 (b), with the same simulation conditions.

As is clear from Figs. 6 (a) to 6 (c), when a conventional probe with no capacitance (assuming a stray capacitance of 0.5 pF) is used, a large voltage drop of 1.32V (44%) occurs. On the other hand, when a capacity of 1000 pF is loaded, the time required for the voltage to stabilize is prolonged, but the amount of change in the voltage is about 0.06 V, which is a very small change of about 2%. The dangling amount can be reduced. Even if the voltage pulsates for a long time, it is not affected at all because the amount of change is small. Also, even when a capacity of 10 OpF is loaded, as shown in Fig. 6 (b), the voltage fluctuation at the power supply terminal is larger than that at 1000 pF, but it is still about 0.18V. Approximately 10%, which is generally the limit of fluctuation, can be sufficiently cleared. In other words, by using a probe loaded with a capacitance of 10 OpF or more as a power supply probe, voltage fluctuations can be suppressed to a level that does not hinder even a very rapid change in current.

As described above, the use of the capacitance-loaded probe as a power supply probe can prevent a voltage fluctuation at the power supply terminal. For example, one of the viewpoints is that the inductance of the power supply probe and the loaded load can be prevented. It is considered that the voltage is compensated by the action of charging and discharging with the increased capacity. As a result, even if the output of the device under test is instantaneously changed from low to high or from high to low due to the signal, Since voltage fluctuations at the power supply terminal can be suppressed, there is no possibility of causing an operation error or forced reset of the device under test, and a very stable test can be performed. In high-frequency / high-speed devices, as described above, a large number of power supply terminals are formed even for a single device, in order to minimize the routing by wiring. Therefore, even if a single power supply probe does not have this large capacity, the capacity to be loaded can be increased by using many power supply probes in parallel. Conversely, even without using a capacity-loaded probe for all power supply probes, the effect of suppressing voltage drop and eliminating noise by the power supply probe can be achieved.

As described above, by using such a capacitance-loaded probe 10 as the power supply probe 4, in order to reduce noise on the power supply line and to prevent fluctuations in the power supply voltage, the higher the capacitance, the lower the frequency of the noise. However, it is preferable because the insertion loss is large and can be attenuated, and the insertion loss at a higher frequency is further increased, and the voltage fluctuation at the power supply terminal can be reduced. However, as described above, there is no problem if a capacitance of 100 pF or more is used for both noise removal and voltage fluctuation, but about 5 OpF or more is sufficient. As described above, the probe itself cannot be made too large in thickness due to high integration, but rather needs to be made thinner, so that the capacity area cannot be increased too much. Therefore, it is preferable to use a dielectric material having a relative permittivity as large as possible as the dielectric layer 15.

On the other hand, signal probes have various signal lines, ranging from those near DC level to RF signals of 1 GHz or more, and 1 GHz for low-frequency signal lines of about 100 MHz or less. The above RF noise may be superimposed, and it is desired to remove these noises selectively. Therefore, by using a capacitance-loaded probe in which the capacitance is selected for each signal terminal according to the frequency of the applied signal, noise can be reliably removed and a highly reliable inspection can be performed. . For example, when the above-described dielectric cylinder is used, barium titanate (relative dielectric constant of about 700 to 2000) and strontium titanate are used as the dielectric material used in such a capacitor loaded capacitor. (Relative dielectric constant: about 150 to 400) In addition to high dielectric constant ceramics, fired ceramics such as high dielectric constant ceramics (relative dielectric constant of about 10 to 50) and alumina (relative dielectric constant of 9 to 10) can be used. Made of a material with a large relative permittivity, such as barium titanate or strontium titanate, allows the use of high-frequency power even for extremely small power supply probes with inner and outer diameters of 0.3 mm, 0.6 mm and a length of about 6 mm. This is preferable because a large capacitance of about 100 OpF or more can be formed to almost completely bypass noise, and even low-frequency noise can be easily removed.

Further, as described later, for example, a thin film can be directly formed on the outer surface of the metal pipe 13 without using a dielectric tube. Examples of such a film forming material include, in addition to the materials described above, lead titanate, lead zirconate titanate (ΡΖΤ; relative dielectric constant of about 700 to 1000), lanthanum lead zirconate titanate (PLZT), titanic acid Bismuth-based compounds such as barium strontium (BST; dielectric constant of about 1000 to 3000), bismuth strontium tantalate (SBΤ), and bismuth titanate (BIT; dielectric constant of 150 to 220) can be used. These materials have a large relative dielectric constant and can be formed in a thin film of about 5 to 20 / m, so it is easy to form larger capacity capacitors.

In the case of the dielectric cylinder type described above, the current does not flow through the capacitor, so the conductivity of the electrodes does not matter much. However, if the dielectric and the metal are not in close contact, a gap with a small dielectric constant is used. Since a portion is formed to reduce the capacity, it is preferable that a metal film is provided in close contact with the inner peripheral surface and the outer peripheral surface of the dielectric cylinder 15. For this reason, the inside of the dielectric tube 15 is also plated with Ni or the like by electroless plating, and then, if necessary, the second conductive film 16 is provided by plating with silver or gold. Similarly, a first conductive film 17 is formed on the surface by electroless plating or the like. Since the inner peripheral surface has a very small diameter of about 0.3 mm, it is difficult for the plating liquid to penetrate.However, the plating liquid is also applied to the inner wall by, for example, evacuating or stirring the plating liquid by ultrasonic waves. It can be sucked up by capillary action, and can be damaged.

FIG. 7 shows an example in which a dielectric thin film 15a is formed directly on the surface of a metal pipe 13 without using a dielectric cylinder as a dielectric layer of a capacitor. That is, this In the example, a dielectric material is directly attached to the outer surface of the metal pipe 13 by sputtering, vacuum deposition, laser ablation, or the like, or the dielectric material is dissolved in an organic solvent and applied to the outer surface of the metal pipe 13. However, the sol-gel method of firing and the like directly increases the outer surface of the metal pipe 13. According to such a direct film formation method, a very thin film of about 5 to 20 / m can be formed, so that a very large capacity can be formed. In addition, the withstand voltage of the insulating film is about 50 V even when the thickness of the PZT is 10 / m, for example, and there is no practical problem. For example, using a metal pipe 13 with a length of 1 mm and an outer diameter of ø0.3 mm, a PZT with a specific dielectric constant of 730 was formed to a thickness of 10 zm, and as a result, the probe was Despite the length of 1/6, a large capacity of 124 OpF was obtained.

When a film is formed by a sputtering method or a vacuum evaporation method, the film can be formed over the entire surface by rotating the metal pipe 13 while rotating. In the case of the sol-gel method, a dielectric film can be formed by applying a solution for a dielectric, drying and firing.

As shown in Fig. 2 (a), the movable pins 11 and 12 are held by a spring 14 in a metal pipe 13 with a narrow opening at the tip, and the tip is pressed. As a result, the spring 14 is contracted by contraction. In the example shown in FIG. 2 (a), movable pins 11 and 12 are provided on both sides, and both the fiber distribution board 6 and the device to be machined 20 are pressed by springs 14. However, as shown in Fig. 8, the wiring board 6 side is fixed by a metal body 19, and if it is securely brought into contact with the wiring 反 1 by direct soldering or the like, the device under test 20 side Only the movable pin 11 may be provided.

As shown in Fig. 2 (a), the movable pins 11 and 1 2 have a structure in which the end of the spring 14 is cut obliquely so that the movable pins 11 and 1 2 When the spring 14 is pressed and contracted, the spring 14 contracts obliquely and is pressed into contact with the narrow opening of the metal pipe 13, and the electric signal transmitted to the movable pin 11 has electric resistance instead of the thin spring 14. Since the signal is transmitted through the small metal pipe 13, the impedance can be reduced as much as possible, and the RF noise can be reduced. In addition, although not shown in FIG. A constricted portion is provided on the side, so that the movable pins 11 and 12 can be formed so as not to fall out. The movable pins 11 of the signal probe 3 and the grounding probe 5 are formed in the same manner.

The metal block 1 holds probes 3 to 5 for signals and power, and is made of a metal plate such as aluminum or brass. A through hole is formed in the metal plate, and the inside of the through hole is formed. These probes are inserted.

If the signal probe 3 is for low and medium frequency signals of, for example, 100 MHz or less, use a capacitance-loaded probe in the same way as shown in Fig. 2 (a), and use it according to the frequency of the input signal. The capacity can be adjusted and used. On the other hand, for RF signals of 1 GHz or higher, a structure with only a spring-loaded movable pin consisting of a metal pipe and a spring and a movable pin installed inside the metal pipe may be used, as shown in Fig. 2 (a). However, the structure is such that a metal pipe is inserted into the through hole of the metal block 1 via a dielectric material around it, and the relationship between the outer diameter of the metal pipe and the inner diameter of the through hole of the metal block 1 is coaxial. It is preferable to form the structure so as to have a dimension that composes the structure, since it is possible to prevent RF noise from being introduced via the movable pin without attenuating the RF signal. The end of the RF signal probe 3 opposite to the connection end to the device under test 20 is connected to a coaxial cable 7 such as semi-rigid.

The wiring board 6 supplies power to the device under test 20 and the like. Wiring is formed on the substrate, and its terminals are appropriately formed at locations corresponding to the terminals of the device under test. In this case, as described above, a single-pass filter is formed between the power supply terminal and the ground terminal on the wiring board 6, or a chip capacitor is connected. Also, instead of the coaxial cable 7 being directly connected to the other end of the signal probe 3 described above, a signal wiring is formed in this wiring counter 6 and connected to the coaxial cable via the wiring. May be.

The holding plate 8 is made of an acrylic plate or the like, is made of a thin electrically insulating material of about 0.1 to 0.2 mm, and is provided with a through hole from which the movable pin 11 of each probe projects, which is not shown. It is fixed with screws. As a result, the metal pipe or insulator of each probe is fixed so as not to protrude from the metal block 1. In the example shown in FIG. 1 (a), the movable pin 11 protruding from the holding plate 8 has a BGA type inspection target. Although shown as an example formed in a matrix so as to correspond to noise 20, the number of signal probes, power supply probes, and grounding probes and their arrangement are to be tested. It is formed according to the power supply terminal of the device under test 20, and for example, an input / output RF signal probe, a power supply probe, and a grounding probe may be formed one by one.

In the example shown in FIG. 1 (b), one end of the probe is fixed by the holding plate 8, but it is not always necessary to use the holding plate. That is, as shown in FIG. 9, a step portion for fixing the end of the probe is provided in the through-hole into which the probe of the metal probe 1 is inserted, and the second metal block 1 a similarly formed with the step portion is provided. , The movable pin 11 can be moved while the probe 10 is fixed by fixing the probe 10 from both sides and fixing the probe to the metal block 1 with screws (not shown) from the second metal block 1a side. .

In the above example, the capacity formed on the outer periphery of the metal pipe 13 is one kind of capacity. However, for example, as shown in FIG. 10 (a), the first metal film is divided. by to length and MM _2, M ₃ different length of the metal film 1 7 a, 1 7 b, 1 7 c, as shown in FIG. 1 0 (b), of different capacity capacity evening 18a, 18b and 18c can be formed. It it Capacity evening C u -C _{1 3} capacity is distributed to the capacity size was proportional to the capacity of the entire length M in the length of the respective lengths M ₁ ~M ₃ of. As a result, when a capacitance according to the frequency of the signal is required as the signal probe described above, only the metal film having the desired capacitance among the metal films 17 a to 17 c having different lengths is made of metal. By contacting with block 1, it can be used as a capacity of desired capacity. Since the high-frequency characteristics differ depending on the material and thickness of the dielectric material forming the capacitance, when selecting a desired capacitance according to the signal frequency, the frequency characteristics also change. Alternatively, by bringing all the metal films into contact with the metal block, it is possible to obtain a frequency characteristic that cannot be achieved with one dielectric.

According to the present invention, since the device to be inspected is contacted by the movable pin, there is no exposed portion of the lead in the contact portion with the electrode terminal of the device to be inspected, and the power supply electrode terminal of the device to be inspected. A capacitor is formed around the power probe to be As a result, RF noise can be removed just before input to the power supply terminal of the device under test, and the test can be performed in a noise-free state. In other words, when testing high-frequency / high-speed devices, it is necessary to reduce the noise as close as possible to the device under test, since it is easy to pick up noise even with a short lead length. Since the capacitance is formed on the power supply probe immediately before contact, noise can be eliminated very effectively, and the voltage drop at the power supply terminal during high-speed switching waveform output should be minimized. Can be.

In addition, at the signal terminals, according to the frequency of the signal, a probe equipped with a capacity that attenuates the RF noise without attenuating the signal at the signal port before inputting it can be used. Also, the noise superimposed on the signal component can be effectively removed before entering the terminal of the device under test.

As a result, the problem of oscillating the amplifier of high-frequency and high-speed devices and the inability to perform accurate device inspections has been solved, and noise has been completely removed from the power supply terminal and signal terminal, making it extremely stable. Accurate inspection can be done. As described above, the power probe may be configured such that only the side in contact with the device under test is a movable pin and the other end is directly connected by soldering, etc. Alternatively, the movable pin may be provided only on the contact side with the device under test, and the other end may be fixed. In addition, since no grounding probe is provided, for example, anisotropic conductive rubber that has a large number of thin metal wires buried in rubber and conducts only in the vertical direction and is insulated in the horizontal direction is used. It is also possible to have a structure in which the metal block 1 and the ground terminal of the device under test are directly connected via the metal block.

According to the present invention, since a contact probe having a movable pin that can reliably contact an electrode terminal or the like of a device to be inspected only by pressing is provided with a direct capacity, a high-frequency / high-speed device When performing the characteristic inspection, it is possible to prevent the voltage drop of the power supply terminal and to prevent the noise from entering from the power supply terminal and the signal terminal while ensuring the contact with the device to be damaged. By adjusting the capacitance of the signal terminal, it is possible to attenuate only the noise without deteriorating the signal. As a result, a very stable test is accurate It is possible to greatly improve the reliability of high-frequency and high-speed devices; (β.

The present invention relates to an amplifier circuit, a mixer circuit, a filter circuit, an IC, a module, a high-speed digital processing processor (DSP (digital signal processor) _s CPU (central processing unit), (field programmable gate array)), high-speed memory, serial-parallel conversion IC (SER ZDES (serializer / de-serializer)), etc. be able to.

Claims

Scope of word blue

(1) a metal pipe, a movable bin provided in the metal pipe so as to be electrically connected to the metal pipe, and having at least a variable projection length protruding from one end of the metal pipe; A capacitor loaded type capacitor comprising: a dielectric layer provided; and a first metal film provided on an outer peripheral surface of the dielectric layer, wherein a capacitance is formed between the movable pin and the first metal film. Bu.

(2) the dielectric layer is formed of a dielectric tube, the first metal film is formed on an outer peripheral surface of the dielectric tube, a second metal film is provided on an inner peripheral surface of the dielectric tube, 2. The capacitively-loaded probe according to claim 1, wherein the probe is electrically connected to the metal pipe via a second metal film. ,

3. The capacity-loaded probe according to claim 1, wherein the dielectric layer is formed of a thin film directly formed on an outer peripheral surface of the metal pipe, and the first metal film is formed on the thin film.

4. The capacity-loaded probe according to claim 1, wherein the capacity provided on the outer periphery of the metal pipe is formed to have two or more types of capacities.

(5) A metal block and a movable pin having a movable distal end with a movable length, and the knitting (3) is provided on one surface side of the metal block so as to penetrate the metal block so that the distal end of the movable pin projects. A plurality of probes for power supply and signal; and a device to be inspected is pressed against the one surface side of the metal block, and each electrode terminal of the device to be inspected is brought into contact with a tip portion of the probe. An inspection jig for inspecting characteristics of the device under test, wherein at least a part of the plurality of probes has a capacity provided by providing a dielectric layer and a metal film on an outer periphery of the probe. ^ ¾ Jig consisting of a capacity-loaded probe with an evening formed.

6 At least some of the signal probes connected to the signal input terminal of the device under test have the repetition in accordance with the repetition of the sine wave or pulse of the signal applied to the input terminal. 6. The jig according to claim 5, wherein a capacitance-loaded probe is used which is provided with a capacity having a capacity to attenuate noise of a frequency higher than the repetition, with a small attenuation for the signal. 7. The jig according to claim 5, wherein the power probe connected to the power terminal of the device to be inspected is a capacitance-loaded probe to which a capacitor having a capacity of 5 O pF or more is connected.

8. The inspection jig according to claim 7, wherein a capacitance-loaded probe having a capacity of 100 pF or more is connected to a power probe connected to a power terminal of the device under test. .